High-dose chemotherapy, with or without radiotherapy, followed by autologous stem-cell rescue is used increasingly for the intensification of first remission in acute myeloblastic leukemia (AML). However, these treatments have been limited to young patients due to the increased risks of regimen-related toxicities and mortality with age. Several investigators have recently published the upper age limit for autologous bone marrow transplant (ABMT) in AML because of encouraging results. The results of ABMT for AML were studied in 111 patients > or = 50 years of age intensified in first remission. Median age at transplant was 53 years (range, 50 to 63 years). Fifty patients were conditioned with total body irradiation and 61 with polychemotherapy: 23 with busulfancyclophosphamide, 11 with the University College Hospital (UCH; London, UK) regimen, 6 with BAVC, and 21 with various other treatments. Marrow was purged in only 11 cases. Results were compared with 786 ABMTs performed for AML in patients between 16 and 49 years of age (median, 35 years). For AML in first remission, the probability of leukemia-free survival (LFS) at 4 years was 34% +/- 5% for patients aged 50 years or more and 43% +/- 2% for patients less than 50 years of age (P = .004), with a survival probability of 35% +/- 6% and 48% +/- 2%, respectively (P = .004). The probability of relapse was not significantly different between the two groups (52% +/- 7% v 50% +/- 2%), but transplant-related mortality was significantly higher in the older age group (28% +/- 5% v 14% +/- 2%; P < .0001) and mainly due to infectious complications. In a multivariate analysis, age less than 50 years was a favorable risk factor for LFS, treatment-related mortality (TRM), and survival but not for relapse incidence. These data suggest that ABMT should be considered in older AML patients.